Images and video showing extent of Oroville dam damage
imgur.com
imgur.com
There was also drainage through the hydro plant, with a maximum capacity of slightly less than 20,000 CFS. This is given in Wikipedia's coverage:
https://en.m.wikipedia.org/wiki/Oroville_Dam_crisis#Backgrou...
https://news.ycombinator.com/item?id=13785549
There is also the issue they are addressing now where debris has blocked water from exiting the power plant pool, preventing operation of the power plant.
If they can get the power plant running things will be much improved, as they will be able to continue to drain the reservoir without further erosion of the main spillway and also until it is below the level of the main spillway (which will stop the small amount of water that is currently leaking through the control gates).
https://ww2.kqed.org/news/2017/02/07/engineers-assess-spillw...
The main spillway is the mechanism by which, when needed on a normal basis, major discharges can be accomplished. That is: its design intent is to accommodate such flows, without failure of itself or incapacitating damage. To that extent, the spillway damage was a massive management failure.
The emergency spillway, as I've only learnt reading up on this story within the past day, was designed as a "use once" capability. It isn't designed for repeated usage, requires massive reconstruction after such uses, and (in conjunction with the parking lot), provides the basis for a "soft failure" of the dam as a whole, as opposed to the prospect of the entire dam face collapsing.
The Auburn Coffer Dam engineered failure has been mentioned (though not linked -- it's easy enough to find on YouTube) elsewhere in this thread. That was a 1986 event during an extreme rain event. The dam, also an earthen structure, was designed with an intentionally soft "plug", that could and would erode before the main dam face, but in a slow fashion, such that the dam would fail over the course of hours, rather than minutes.
The rate of occurrence of things matters, and a factor of 60 or so (as above) is tremendous. As a comparison, you're in a car moving at 100 kph, and are later moving at 0 kph. How do you feel?
If the interval is 20s, probably pretty good. If it's 0.02s, likely not so hot.
That's a rate difference of 1,000 fold. Something to keep in mind in the context of other stories, such as, say, the fact that climate is change at a rate of roughly 1,000,000x faster than normal, presently.
A point Tucker Carlson apparently cannot grasp, given a recent appearance of Bill Nye on his programme.
The normal way water flows out of that dam has nothing whatsoever to do with either the spillway, or the emergency spillway, and was not shown in the series of photos.
Semantic means "relating to meaning" and indeed different words have different meanings. Meanings actually matter, it turns out. In this case, the meanings are different enough that you would have to take a two minute or so walk to get from one water outlet (the normal one) to another (either of the two spillways).
The value of the montage here is editing down a large set of images and footage to the critical and suffient element.
As is writing, or audio, or anything else.
I see far too many people who think recording is synonymous with authoring or creating. As Stephen Colbert commented some time back (and many others before him), steganography isn't news.
I've been kicking around a lot of ideas concerning narrative, the thread that organises a story -- fictional, expository, explanatory, whatever. P.D. James' quote on what the heart of a novel is, bringing order to mystery, is apropriate as well.
I found myself watching some of the videos over and over, and skipping others with only a cursory glance. The text was easy to read.
When I watch videos with text I find myself pausing a lot. And nothing is more annoying than trying to rewind a long video to re-watch a 5 second clip: I'm always overshooting and wasting a ton of time.
Reminds me of the "multimedia" of the 90s. :)
This is literally all that site is. Check out, for instance, https://reddit.com/r/diy. It is all just imgur albums.
Reuter's had a picture gallery just a couple days ago that shows the damage much better:
http://www.reuters.com/news/picture/massive-damage-at-califo...
I disagree that that's a better collection, on a number of counts:
1. The presentation is a fixed-size image on the page, which cannot be maximised (or the controls for such maximisation are highly nonobvious). Which means that I'm seeing a roughly 1/4 size image with vastly less detail than in the Imgur collection.
2. Despite what is clearly access to an arial vehicle (probably a helicopter), the Reuters images present a much smaller set of viewpoints, perspectives, and scales. The flexibility of a drone to go virtually anywhere within the area of interest, the specific focus on both the main spillway and the emergency overflow, the massive erosion along the latter, and the ability to either move in (not just zoom in via lens), or back out for an overview, is highly apparent in the Imgur photosets.
3. By contrast, the drone images provide a range of perspectives, sightlines, an distances from the subject, giving a much better overview of the full scope of the incident.
4. The Reuters images are static, not animated. Whilst I'm among the first to agree that animations can be, and are, overused, their use to show dynamic changes or events is exceedingly useful, and used to exceedingly good effect in the Imgur set.
5. Several of the Imgur images (you have to expand to see the full set) do show the extreme extent of the damage, including the void carved out below the initial failure, the gully formed by the free-flowing water, and the damage downstream of the spillway collapse showing visible rebar at the spillway lip, erosion of that lip, damage to the water diverting teeth at the bottom of the spillway, and several sections of channel wall which have been destroyed upstream of the lip. Also shown are multiple shots with humans visible for scale (and a banana).
6. The captioning of the Imgur slides is far more descriptive than those of the Reuters shots. Passive voice is avoided in the Imgur captions. Because passively voicing your captions is not only dry as fuck but creates a massive tendency to eliminate virtually any informative value from those captions.
7. Finally, the Imgur collection can be contrasted with the imagery which typically accompanies news stories: close-in shots generally of either emergency workers, evacuees, or onlookers, with little or no contextualisation of the larger picture. If you're exceedingly lucky, a small line map with minimal detail may be provided, showing approximate locations, but virtually nothing of interest as to the situation or considerations of the scene or its larger surroundings. For broad-scale disasters (fires, floods, hurricanes, earthquakes), there's almost never a map showing extents, damage, or more critically, safe evacuation zones in the immediate vicinity of an event. This is where I've found Wikipedia to be almost without exception the single best source of information an overview of an ongoing event, in that it synthesises the overall understanding of an event to that point in time, rather than providing a drip of what is almost always very little news, that entirely uncontextualised, and in broadcast media, an absolutely insane amount of space-filling tap dancing and repetition.
My vote goes with the Imgur collection.
Incidentally, Imgur allows animations to be stopped, via most clients, by clicking the image or the animation controls themselves. You don't have to leave them running. I also find muliple simultaneous animations distracting.
California had a gold rush - part of the gold mining was done using "hydraulic mining", where you use water to scrub away rock and direct it into a channel for the runoff to be run through mining equipment.
Be sure, there are plenty of gold prospectors downstream panning or perhaps even using metal detectors in the areas where the waters have receded, looking for golden flakes ("flour") and nuggets.
I don't know the exact law in CA but in general you can use human-powered methods without mechanical assistance, to pan for gold (basically what looks like a pie-pan which has ridges inside to catch the heavier gold).
Source: https://www.amazon.com/Introduction-California-Natural-Histo... (kind of "dry", but extremely informative)
Or more accurately, it jiu-jitsu's the potential energy in the system to redistribute the resource in a more optimal way (optimal defined as "best for the human economy of california")
[1] https://www.amazon.com/Cadillac-Desert-American-Disappearing...
or even that the dam served that purpose. thanks for sharing.
As you can see from the pictures, the "bedrock" under the emergency spillway erodes quickly, even with a modest amount of water flowing over it. How would it have handled a flow 100x larger, if the spillway structure had collapsed?
It could have easily eroded down 100 or 200 feet under the intense flow. That would have discharged 50% of the total reservoir volume, destroying tens of billions in real estate and possibly killing thousands.
Fortunately, the dam inflow slowed enough, combined with the main spillway outflow, to stop flow over the emergency spillway before it collapsed. So lucky.
I asked about that and he pointed out that the dam was failing, and we were watching it fail. He pointed out the spillway shooting sideways and the amount of progress it had made in just the couple of days between the emergency spillway issue and then. He drew a line on the screen showing how the water cuts away the rocks and that the material above falls in, and becomes like sanding bits in the water flow to cut away still more rock. He estimated that two more weeks of rain at the levels we had experienced would result in total failure.
None of which the press was reporting. And we talked about why that might be. And other than the loss of life (which could be minimized by an evacuation order) there wasn't a whole lot they could do. They certainly couldn't repair the dam while water was flowing out of it. But at the same time they would have a several days at least of knowing it was going to fail before it actually did because of the amount of material that would need to be removed.
He suggested that it was in everyone's best interest to keep the panic and stress levels low until they needed to be higher. And I can't say I disagreed although felt it would be really annoying to have my stuff washed away when folks knew it was a possibility and didn't even offer me the chance to move it first.
So cross your fingers for a sunny March and a slow melt of the Sierra snow pack.
They were more concerned about getting the evacuees out of the way before they were worried about getting the evacuees' stuff out of the way. Houses, furniture, and belongings can be replaced after a disaster. A bunch of people twiddling their thumbs in anxiety over a potential failure while not ordering evacuations to minimize or prevent loss of life is potentially criminal.
Also, people tend to panic. Telling them that there is a probable problem, and ordering a mandatory evacuation long before danger is imminent so that, if the worst case scenario occurs, the evacuees will live gives people hope that officials are just being overly cautious. Telling people that they have 5 hours to evacuate before it is guaranteed that all of their belongings, and their lives, will be lost forever will cause panic and potentially loss of life in the chaos alone.
That's the part where they risk being wrong and end up getting a thousand people killed. The notion of cutting that so close, such that just several days is the buffer between killing a thousand or more people and not, is a very obnoxious premise if that's what they were actually doing.
Looks like the side of the spillway or roadway was damaged, since the concrete appears to be broken, although the spillway wall itself might be ok below that vantage point. It's just really hard to tell from that angle, but all of the official drone footage/photos from DWR don't include that area of the spillway, which is curious.
"The uniform, free surface, turbulent water flows down an inclined, wide, rectangular open channel may become unstable spontaneously, if some sufficient conditions are satisfied. As a result, steady hydraulic conditions are interrupted, including the water depth (or pressure) and flow velocity. When the channel is sufficiently long, the small instabilities on the water surface will develop to a series of intermittent shock-like waves separated by sections of the gradually varying flow."
We know that momentum (mv) is always conserved. In this context, we can replace mass with cross-sectional area, because mass in a given cross-section is proportional to the area. V is flow velocity in length/time. So momentum is flow in length^3/time.
Energy is 1/2mv^2. If you lose energy, mv is constant and m*v^2 decreases, meaning that v must decrease and m must increase. In this context, that means that the flow is slower with a larger area. This corresponds to an "inelastic collision". In fluid dynamics this is a hydraulic jump.
In this situation, most of the energy loss is near the surface, so you end up with moving hydraulic jumps on top of a laminar flow. This doesn't really happen in natural situations, because riverbeds generally aren't this smooth.
When I first noticed it, I was reminded of waterfalls, especially the way they were portrayed in 8 bit games. [1] It turns out not to be that easy to find a good real world example, at least not without watching hours of waterfall footage, but this one [2] does an acceptable job showing it. I have no idea if this could be caused by the same or at least a similar mechanism.
In this video from 1st March he visits the site and surrounding areas and talks with some of the engineers working on the project:
First, you went from a prolonged severe drought to a very intense rainfall in a very short amount of time, extremely not helped by the massive surface runoff when the emergency spillway was put in use. I don't know all of the geological processes involved, but the upper soil layers were probably made far more mobile and less stable by the drought.
Second, the massive erosion is happening on a slope, whereas the Grand Canyon is (comparatively) flat. A steeper gradient means less force is needed to set sediment in motion.
If you want impressive floods, the Bonneville and Missoula floods are the largest known floods in history. Imagine floods with hundreds or thousands of times the flow rate of Niagara Falls, which cumulatively scoured the Columbia river region by hundreds of feet.
There are examples where rivers are much older than the mountains they pass through - like the Susquehanna:
So I follow the Little Colorado expecting an easy drift into camp but instead I have a gale force headwind and serious bits of uphill. So I didn't get there and I had to sleep in the tent held up by rocks with no let up in the wind, with an electrical storm to follow, one where I was the highest metal object around...
Next morning I woke up rough and set off on my bike, literally 1/2 mile away up the road were a group of cycle tourists from Yugoslavia and they pitched up in one of the roadside stalls. Had I not given in so easily the previous night I would have had a fun time meeting up with them and drinking properly... I was also oblivious to the time zone change so the next day came with a 'free' hour too.
I did go down to the very bottom of the Canyon and up the other side to continue my cycle tour of the wonderful U.S.A. These crazy dams (every river is dammed) were a huge part of my time there, riding across them and camping by them.
"U.S. Geological Survey hydrologist Jim O'Connor and Spanish Center of Environmental Studies scientist Gerard Benito have found evidence of at least twenty-five massive floods, the largest discharging ≈10 cubic kilometers per hour (2.7 million m³/s, 13 times the Amazon River). Alternate estimates for the peak flow rate of the largest flood include 17 cubic kilometers per hour and range up to 60 cubic kilometers per hour."
Fascinating geology and scarily impressive traces. Makes me wonder what will happen on Greenland or Antarctica.
The symbolic and scientific significance are large. This is an exceedingly large ice mass, it may persist for years, possibly decades, in the Southern Ocean. It may pose a threat to shipping (though there's comparatively little through the region), and may have impacts on local biology and ecosystems (habitat loss, habitat gain, habitat change).
The mechanisms of loss, calving, migration, persistence, and of resulting changes to land-based glacial flow, will be fascinating.
But in terms of portending a drastic increase of ice flows local to it, the calving has little impact, as compared to, say, a shelf loss proximate to the primary Antarctic land mass -- the Ross or Weddel shelves, for example, which have behind them a thousand kilometers and more of kilometer-thick ice. That will be an interesting occurrence.
Or the formation and destruction, say, of ice dams, on the Antarctic continent or Greenland, creating meltwater pools, perhaps hundreds of kilometers in extent, and suddenly releasing those, as the dams erode, into the oceans. Similar mechanisms created a badlands landscape in eastern Washington State as the prehistoric Lake Missoula formed and drained, perhaps dozens of times, releasing cubic kilometers of water in massive scours. A similar mechanism, probably in Canada, triggered a catastrophic sea-level rise, measured as I recall in meters, over the course of days to a month.
That would also make for an interesting news cycle.
Contextualisation of these types of events in the press is exceedingly poor, with a small handsful of exceptions. I've already mentioned Brad Plumer's Vox coverage in this thread, he's among the exceptions.
https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_...
Was this way more rain than it was designed for? Or was it structural failure within design tolerances that caused all the damage?
The main spillway is the concrete spillway, and it developed a hole in late January. Due to very real concerns that it would deteriorate, the decision was made to use the emergency spillway until the concrete spillway would be fixed.
The emergency spillway is basically a concrete weir--when the lake level reaches a certain height, it spills out over concrete and runs down the hillside. This is considered an emergency spillway, and erosion is usually expected for such spillways (the regulatory definition of an emergency spillway is basically "it can be used once and then it needs a long downtime while it's repaired).
When the emergency spillway was in use, what happened was the very same erosion that was underpinning the main spillway was also occurring near the concrete weir. If left unchecked, the fear was that it would start eroding the concrete weir leading to potential collapse of the concrete weir. This prompted the decision to evacuate as much water as possible using the damaged main spillway which greatly exacerbated the damage (as the pictures show, a large section of the spillway now fails to exist, and it looks like most of the lower spillway would need to be torn up instead of being unused).
I'm not a geologist, and I certainly don't have detailed nature of the local geology. But my suspicion is that the prolonged drought followed by the intense wet season destabilized the slope (by weakening the organic stabilization of the slope and then loading it heavily with water), so spilling any dam water anywhere on it would lead to massive erosion (including undermining the concrete structures). The emergency spillway is supposed to be able to carry far more water loads. I don't think the severe-drought-then-extreme-rain scenario was envisioned during the dam construction (although it really should be after this event), so I don't know if the spillway would have performed as badly in "expected" conditions.
So yeah, i don't think the dryness had anything to do with destabilizing anything. Water is just really good at cutting. The dam created a huge reserve of water, so lots is available to cut.
https://en.m.wikipedia.org/wiki/Institute_for_Creation_Resea...
Dont underestimate water and human greed.
Present damages now exceed $100m, and repairs are likely to be several times the initial estimates.
In reality, it failed well before the stated tolerance and developed holes. Once that happened all bets were off.
Wikipedia has more info; it gives the capacity of the gates above the spillway as 150,000 cu ft/s, and says the spillway developed cracks in 2015.
If the spillway doesn't experience structural failure, there's no problem. But it did, so flow through the spillway had to be reduced, which led to the emergency spillway coming into play and they had to continue using the damaged spillway, failure or not.
The unusually wet year and failure of the emergency spillway then forced them to run the main spillway at a high rate despite the damage.
But I'm more inclined to suspect the problem is larger. For example that anthropogenic climate change is increasing the amplitude of the El Nino effect.
http://www.mercurynews.com/2017/02/12/oroville-dam-feds-and-...
More than a decade ago, federal and state officials and some of California’s largest water agencies rejected concerns that the massive earthen spillway at Oroville Dam — at risk of collapse Sunday night and prompting the evacuation of 185,000 people — could erode during heavy winter rains and cause a catastrophe.
Three environmental groups — the Friends of the River, the Sierra Club and the South Yuba Citizens League — filed a motion with the federal government on Oct. 17, 2005, as part of Oroville Dam’s relicensing process, urging federal officials to require that the dam’s emergency spillway be armored with concrete, rather than remain as an earthen hillside.
The groups filed the motion with FERC, the Federal Energy Regulatory Commission. They said that the dam, built and owned by the state of California, and finished in 1968, did not meet modern safety standards because in the event of extreme rain and flooding, fast-rising water would overwhelm the main concrete spillway, then flow down the emergency spillway, and that could cause heavy erosion that would create flooding for communities downstream, but also could cause a failure, known as “loss of crest control.”
While there was a lot of rain, and climate change is affecting long-term weather patterns, I think it would be misleading to associate the Oroville Dam problems to climate change.
I'd like to also present Wikipedia's article on the Oroville Dam Spillway Crisis of 2017, which is another example of exemplary coverage, and what's been a consistent model for me for vastly better coverage of ongoing large-scale events since the Boxing Day Earthquake and Tsunami of 2004, the first time I'd followed a major story by way of Wikipedia:
https://en.m.wikipedia.org/wiki/Oroville_Dam_crisis
In roughly 25 paragraphs, plus an SVG image essay showing the progression of the damage, apparently original work by a Wikipedia editor, this spells out the background, event, development, implications, and history of the failure.
Both the Imgur essay and the Wikpedia article are vastly more informative than any news coverage I've seen. In the case of Wikipedia, much of that comes from its ability to synthesize information from multiple sources and place it in a coherent context. But in both cases, much of the value also comes from a focus on what I see as the salient factors, and an avoidance of fluff.
Taking a quick second look at the Wikipedia page, the one fault I'd give it is that for someone immediately affected by evacuation orders, there is insufficient information about what routes were recommended or deprecated. For that, some local news accounts (I'd read the Sacramento Bee and SF Chronicle's coverage in particular) was perhaps more useful, but only just.
I'd put hard to the press just what they see their mission as in reporting on such events. Because, much as I appreciate the media, they fell down here.
Addendum: Brad Plumer, at Vox, has previously caught my attention as an exceptionally good reporter. His article explaining the Oroville Dam crisis is cited by Wikipedia, and is itself also excellent. I'm calling it out specifically as an example of How to Do Coverage Right:
http://www.vox.com/science-and-health/2017/2/13/14598042/oro...
one of several recommended videos about the topic, this one is quite funny even if it's very real: https://www.youtube.com/watch?v=Wpzvaqypav8&feature=youtu.be...
https://www.youtube.com/watch?v=ilkU_ivYTqQ
It's really quite impressive, the scope of the project and how quickly resources have been mobilized to solve the issue.
The water management and power provided by the dam pretty much guarantee it will be repaired and continue operating.
That is quite a bit of water rushing down that way.
Interesting times and the videos are quite educational.
“The damage is catastrophic,” said Brad Foster, who has waterfront property in Marysville (Yuba County), about 25 miles south of Lake Oroville.
The farmer not only saw 25-foot bluffs collapse, but also lost irrigation lines to his almonds. “When the bank pulled in,” he said, “it pulled the pumps in with it. It busted the steel pipes.”
http://www.sfchronicle.com/bayarea/article/Riverbanks-collap...
I'm sure there will be dozens of "good reasons" why the repairs could not have been done in time, but the theme of the approach to infrastructure problems is disheartening.
The main dam of course did not fail, but looking at the recent photos, the overall system sure did fail. I hadn't realized the extent to which the spillway had continued to erode.
A failure of the emergency spillway would still be quite destructive, of course.
When you look at photos or drone videos of the erosion near the main spillway, it's clear that an immense amount of rock has been eroded away (the color changes from brown to gray). [2]
Juan Browne discusses the type and strength of the rock in one of his excellent videos about the Oroville crisis. [3] (Note that he demonstrates the weakness of the rock where he is standing, which is across the river from the spillway and might not be the same rock.)
[1] http://www.mercurynews.com/2017/03/03/spoil-sites-for-orovil...
Another wild guess: the main spillway hasn't eroded any bedrock, just concrete, dirt, loose rocks, etc.
If anyone actually knows versus my wild guesses, I'd be most interested.
Yes, bedrock is not indestructible, it could get eroded from water, but it takes times. Plus it get eroded slowly over time. The main concerns was the use amount of water released by the failure of the spillway. For sure the water keep flowing over the collapse spillway would erode the bedrock lowering it, but at a slower pace...
Having the main spillway continue to erode is pretty clearly a failure state of the dam system.
One thing I'm really impressed with is how many redundancies are built in to dams, and how their failures are intended to be gradual and not catastrophic and sudden with a full release of the reservoir contents.
ie, use the water to generate electricity. If that's not enough outflow, use the spillway. If the spillway isn't enough, the emergency spillway will drain more.
There's even another contingency (with more details), described here, that I haven't heard anywhere else:
http://blogs.agu.org/landslideblog/2017/02/14/oroville-dam-s...
> The emergency spillway is not auxiliary, and i don’t believe any competent geologist present during it’s construction would have considered its use as anything but a last ditch effort. It was designed as a fail-safe to prevent the loss of the main dam during the event of a half a million cfs inflow to the lake during a 200 to 1000 year event. The ogee weir extending from the main spillway gates was likely built to protect the main spillway gates. The bedrock was excavated deeper below the ogee weir to find more competent bedrock than the concrete wall extending northwards from the ogee weir, which was built to protect the ogee weir. The lack of concrete in the far NW corner of the parking lot where we saw considerable erosion and helicopters lowering bags of rocks into is not lack of foresight, but designed weakness built into a weak structure. The parking lot is built on highly weathered bedrock and is designed to function as a sacrificial plug located as far from the dam itself as possible, similar to the Auburn coffer dam failure of 1986. As headcutting progresses into the parking lot, water at elevation 900 and above is skimmed off. Once headcutting reaches the lake, then downcutting commences, “safely” lowering the lake till competent bedrock is found, maybe a hundred feet down, leaving the vast majority of the lake still in the lake and Oroville dam still standing, no matter the magnitude of the storm.
Right now, the lake level has been dropped to 50 feet below the dam top, to provide some safety margin for later storms. The crisis is probably over, and there will be heavy construction this summer.